This invention relates to combustion chamber structures which are utilised for the burning of fuel/air mixtures, so as to produce a gas which in turn is ejected into a turbine which is then rotated by the ejection force which is exerted thereon.
A combustion chamber is constructed from a number of pieces of preformed sheet material. The form of a combustion chamber may be barrel like and have ends the upstream end being dome shaped and the downstream end formed so as to terminate in a portion of an annulus. Thus when a ring of combustion chambers is assembled, their downstream end extremities together make up a substantially complete annulus which matches the inlet annulus of a turbine stage.
In another arrangement, the number of barrel like combustion chambers are dispensed with and a single, annular combustion chamber is utilised. In the latter arrangement, the upstream end is defined by curves in places radially of the annulus axis, instead of curves in all planes radially of the barrel axis as in the former example, and the downstream extremity is of course, entirely annular.
Further, the curved upstream end of the annular combustion chamber will include a number of equally angularly spaced apertures therein, suitable for the receipt of fuel injection means and air swirling means. The upstream end of each barrel like combustion chamber has only one such aperture.
The unavoidable method of construction of combustion chambers is from several parts which are welded together, generates problems in use. Thus some of the parts operate in higher temperatures than other parts. Local expansion/contraction rates thus vary and cracking results. The upstream curved end is particularly susceptible to cracking and therefor, the present invention seeks to provide an improved construction for a combustion chamber of a gas turbine engine.